BACKGROUND As a critical early event in hepatocellular carcinogenesis,telomerase activation might be a promising and critical biomarker for hepatocellular carcinoma(HCC)patients,and its function in the genesis and tre...BACKGROUND As a critical early event in hepatocellular carcinogenesis,telomerase activation might be a promising and critical biomarker for hepatocellular carcinoma(HCC)patients,and its function in the genesis and treatment of HCC has gained much attention over the past two decades.AIM To perform a bibliometric analysis to systematically assess the current state of research on HCC-related telomerase.METHODS The Web of Science Core Collection and PubMed were systematically searched to retrieve publications pertaining to HCC/telomerase limited to“articles”and“reviews”published in English.A total of 873 relevant publications related to HCC and telomerase were identified.We employed the Bibliometrix package in R to extract and analyze the fundamental information of the publications,such as the trends in the publications,citation counts,most prolific or influential writers,and most popular journals;to screen for keywords occurring at high frequency;and to draw collaboration and cluster analysis charts on the basis of coauthorship and co-occurrences.VOSviewer was utilized to compile and visualize the bibliometric data.RESULTS A surge of 51 publications on HCC/telomerase research occurred in 2016,the most productive year from 1996 to 2023,accompanied by the peak citation count recorded in 2016.Up to December 2023,35226 citations were made to all publications,an average of 46.6 citations to each paper.The United States received the most citations(n=13531),followed by China(n=7427)and Japan(n=5754).In terms of national cooperation,China presented the highest centrality,its strongest bonds being to the United States and Japan.Among the 20 academic institutions with the most publications,ten came from China and the rest of Asia,though the University of Paris Cité,Public Assistance-Hospitals of Paris,and the National Institute of Health and Medical Research(INSERM)were the most prolific.As for individual contributions,Hisatomi H,Kaneko S,and Ide T were the three most prolific authors.Kaneko S ranked first by H-index,G-index,and overall publication count,while Zucman-Rossi J ranked first in citation count.The five most popular journals were the World Journal of Gastroenterology,Hepatology,Journal of Hepatology,Oncotarget,and Oncogene,while Nature Genetics,Hepatology,and Nature Reviews Disease Primers had the most citations.We extracted 2293 keywords from the publications,120 of which appeared more than ten times.The most frequent were HCC,telomerase and human telomerase reverse transcriptase(hTERT).Keywords such as mutational landscape,TERT promoter mutations,landscape,risk,and prognosis were among the most common issues in this field in the last three years and may be topics for research in the coming years.CONCLUSION Our bibliometric analysis provides a comprehensive overview of HCC/telomerase research and insights into promising upcoming research.展开更多
Telomerase activity and the expression of telomerase subunits (for example, telomerase reverse transcriptase and telomerase associated protein 1 and telomerase RNA component) of peripheral white blood cells were detec...Telomerase activity and the expression of telomerase subunits (for example, telomerase reverse transcriptase and telomerase associated protein 1 and telomerase RNA component) of peripheral white blood cells were detected in the patients with acute myelogenous leukaemia (AML) and the correlation between telomerase activity and the expression of telomerase subunits was observed. In 94 peripheral white blood cells from 18 healthy volunteers and 76 patients with AML, including 31 AML at initial presentation, 24 at relapse and 21 at complete remission, the telomerase activity and telomerase subunits mRNA or RNA were detected by PCR ELISA and RT PCR respectively. The results showed that the positive rate of telomerase from patients with AML at initial presentation, at relapse and at complete remission was 74.1 %, 79.2 % and 4.8 % respectively. The positive rate of telomerase reverse transcriptase mRNA from healthy volunteers, AML at initial presentation, AML at relapse and AML at complete remission was 5.6 %, 80.6 %, 83.3 % and 9.5 % respectively. The positive rate of telomerase associated protein 1 mRNA and telomerase RNA component in all samples were 100 %. It was suggested that the up regulation of telomerase activity and the expression of telomerase reverse transcriptase is correlated closely with the occurrence and relapse of AML, so telomerase activity and the expression of telomerase reverse transcriptase may be used to estimate the curative effect and predict relapse of AML. Moreover, the up regulation of telomerase activity is correlated with the expression of telomerase reverse transcriptase significantly.展开更多
Objective: To investigated the e?ect of inhibition of telomerase with hTERT antisense on leukemic cells (HL-60 and K562) to CDDP-induced apoptosis. Methods: Antisense phosphorothioate oligodeox...Objective: To investigated the e?ect of inhibition of telomerase with hTERT antisense on leukemic cells (HL-60 and K562) to CDDP-induced apoptosis. Methods: Antisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and puri?ed. Telomerase activity was detected by Telomerase PCR ELASA kit and cell apoptosis was observed by morphological method and determined by ?owcytometry. Results: AS PS-ODN could signi?cantly inhibit telomerase activity by down regulat- ing the hTERT expression, and increase the susceptibility of leukemic cells to CDDP-induced apoptosis. Conclusion: Inhibition of telomerase with hTERT antisense can increases the susceptibility of leukemic cells to CDDP-induced apoptosis.展开更多
Aim To investigate the effects of trichostatin A （TSA） on telomerase activity and the expression of human telomerase reverse transcriptase （hTERT） during apoptosis in vitro and the mechanisms in HL-60 cells. Metho...Aim To investigate the effects of trichostatin A （TSA） on telomerase activity and the expression of human telomerase reverse transcriptase （hTERT） during apoptosis in vitro and the mechanisms in HL-60 cells. Methods The proliferative activity of HL-60 cells was assessed by MTT assay. Cell apoptosis was analyzed by flow cytometry. Telomerase activity was examined by TRAP-ELISA. The expression of telomerase subunits was analyzed by RT-PCR. Results A time- and dose-dependent inhibition was detected in HL-60 cells treated with TSA. After treatment with 600 nmol· L^-1 TSA for 48 h, the apoptosis rate in HL-60 cells was 42. 6% and telomerase activity decreased 1.95 ± 0.25, 1.73 ± 0. 12, and 1.52 ± 0. 09 for 12, 24, and 48 h, respectively. The expression of hTERTmRNA decreased. No significant changes were observed in the expression of hTRmRNA and hTPI mRNA. Condusion TSA inhibits telomerase activity and induces apoptosis in HL-60 cells. The underlying mechanism may be related to the down-regulation of hTERT transcription.展开更多
To detect the expression of telomerase subunits （human telomerase reverse transcriptase, human telomerase associated protein 1 and human telomerase RNA） in gastric cancer and to examine the role that different telom...To detect the expression of telomerase subunits （human telomerase reverse transcriptase, human telomerase associated protein 1 and human telomerase RNA） in gastric cancer and to examine the role that different telomerase subunits play in the gastric carcinogenesis, reverse transcription-polymerase chain reaction （RT-PCR） was used to detect telomerase suhunits messenger RNA in 24 samples of gastric cancer and corresponding non-cancerous tissue. The results showed that the positive rate of hTERT mRNA from gastric cancer and corresponding non-cancerous tissues was 100% and 25 %, respectively. The former was significantly higher than the latter （X^2 = 26.4, P〈0.01）. The positive rate of hTEP1 mRNA from gastric cancer and corresponding non-cancerous tissues was 100 % and 91.7%, respectively and no significant difference was found between them （X^2 =2.1, P〉0.05）. The positive rates of hTR for gastric cancer and corresponding non-cancerous tissues were both 100 % and no significant difference existed between them. It is concluded that in contrast to hTEP1 and hTR, the up-regulation of hTERT mRNA expression may play a more important role in the development of gastric cancer.展开更多
AIM: To investigate synergism of inhibition of telomerase activity and proliferation of human colon cancer cells by combination of telomerase antisense oligonucleotides (ASODNs) simultaneously targeting human telomera...AIM: To investigate synergism of inhibition of telomerase activity and proliferation of human colon cancer cells by combination of telomerase antisense oligonucleotides (ASODNs) simultaneously targeting human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) in vitro. METHODS: ASODN of hTR and ASODN of hTERT were transfected into human colon cancer SW480 cells by liposomal transfection reagents. Telomerase activity of SW480 cells was examined using telomeric repeat amplification protocol (TRAP)-enzyme-linked immunosorbent assay (PCR-ELISA). Proliferation activity of SW480 cells was tested by methyl thiazolyl tetrazolium assay. Apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: The telomerase activity and cell survival rate in SW480 cells transfected with 0.2 μmol/L of ASODN of hTR or ASODN of hTERT for 24-72 h were significantly decreased in a time-dependent manner compared with those after treatment with sense oligonucleotides and untreated (telomerase activity: 24 h, 73%, 74% vs99%, 98%; 48 h, 61%, 55% vs98%, 99%; 72 h, 41%, 37% vs 99%, 97%; P<0.01; cell survival rate: 24 h, 88%, 86% vs594%, 98%; 48 h, 49%, 47% vs94%, 97%; 72 h, 44%, 42% vs92%, 96%; P<0.01). Moreover, the telomerase activity and the cell survival rate in SW480 cells treated by the combination of telomerase anti-hTR and anti-hTERT were more significantly suppressed than single anti-hTR or anti-hTERT (telomerase activity: 24 h, 59% vs 73%, 74%; 48 h, 43% vs61%, 55%; 72 h, 18% vs41%, 37%; P<0.01; cell survival rate: 24 h, 64% vs88%, 86%; 48 h, 37% vs49%, 47%; 72 h, 25% vs44%, 42%; P<0.01). Meanwhile, the apoptosis rates in the combination group were markedly increased compared with those in the single group (24 h, 18.0% vs7.2%, 7.4%; 48 h, 23.0% vs13.0%, 14.0%; 72 h, 28.6% vs 13.2%, 13.75; P<0.01). Cells in combination group were arrested at G0/G1 phase. CONCLUSION: Telomerase anti-hRT and anti-hTERT suppress telomerase activity, and inhibit growth of human colon cancer cells probably via induction of apoptosis and retardation of cell cycle. Additionally, combined use of telomerase ASODNs targeting both hTR and hTERT yields synergistic action selective for human colon cancer.展开更多
A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was bette...A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was better in reproducibility and accuracy. Using this method, we found telomerase activities were absent in normal human liver cells, while detected in ail of four human hepatoma cell lines (BEL-7404, SMMC-7721, QGY-7903 and HCCM) without significant differences.展开更多
To investigate the effects of sodium selenite on telomerase activity and expression of hTERT mRNA in cadmium-transformed 16HBE cells. Methods Telomerase activity and expression of genes were measured after cultured ca...To investigate the effects of sodium selenite on telomerase activity and expression of hTERT mRNA in cadmium-transformed 16HBE cells. Methods Telomerase activity and expression of genes were measured after cultured cadmium-transformed 16HBE cells were exposed to sodium selenite at different doses （0.625, 1.25, 2.50, 5.00 pmol/L） for 24 hours. Results Selenium decreased telomerase activity in cadmium-transformed 16HBE cells. There existed an obvious dose-effect relationship between the selenium concentration and these changes. The expression of hTERT and c-myc mRNA also decreased but the expression of madl mRNA increased after exposure to selenium for 24 hours. No difference was found in expression of hTRF1 and hTRF2 mRNA after incubated with sodium selenite for 24 hours, compared with control group. Conclusion Selenium inhibits telomerase activity by decreasing hTERT and c-myc mRNA expression and increasing madl mRNA expression in cadmium-transformed 16HBE cells and selenium concentration is significantly correlated with these changes.展开更多
AIM: To investigate telomerase activity and human telomerase reverse transcriptase (hTERT) expression in normal human gastric mucosal epithelial cells (nhGMECs) and fibroblasts (nhGMFs).
Colorectal cancer(CRC)is the third most common cancer worldwide and,despite improved treatments,is still an important cause of cancer-related deaths.CRC encompasses a complex of diseases arising from a multistep proce...Colorectal cancer(CRC)is the third most common cancer worldwide and,despite improved treatments,is still an important cause of cancer-related deaths.CRC encompasses a complex of diseases arising from a multistep process of genetic and epigenetic events.Besides heterogeneity in the molecular and biological features of CRC,chromosomal instability is a hallmark of cancer and cancer cells may also circumvent replicative senescence and acquire the ability to sustain unlimited proliferation.Telomere/telomerase interplay is an important mechanism involved in both genomic stability and cellular replicative potential,and its dysfunction plays a key role in the oncogenetic process.The erosion of telomeres,mainly because of cell proliferation,may be accelerated by specific alterations in the genes involved in CRC,such as APC and MSH2.Although there is general agreement that the shortening of telomeres plays a role in the early steps of CRC carcinogenesis by promoting chromosomal instability,the prognostic role of telomere length in CRC is still under debate.The activation of telomerase reverse transcriptase(TERT),the catalytic component of the telomerase complex,allows cancer cells to grow indefinitely by maintaining the length of the telomeres,thus favouring tumour formation/progression.Several studies indicate that TERT increases with disease progression,and most studies suggest that telomerase is a useful prognostic factor.Plasma TERT mRNA may also be a promising marker for the minimally invasive monitoring of disease progression and response to therapy.展开更多
This study investigated the effect of cadmium on the telomerase activity,the expression of TERT,c-myc and p53 and the apoptosis of rat hepatocytes.The rats were administrated 5,10 and 20 μmol/kg cadmium chloride intr...This study investigated the effect of cadmium on the telomerase activity,the expression of TERT,c-myc and p53 and the apoptosis of rat hepatocytes.The rats were administrated 5,10 and 20 μmol/kg cadmium chloride intraperitoneally and sacrificed 48 h after the initial treatment.The telomerase activity of the rat hepatocytes was measured by the telomeric repeat amplification protocol (TRAP),and apoptosis was detected by flow cytometry.The mRNA expressions of TERT,c-myc and p53 were measured by reverse transcription-polymerase chain reaction (RT-PCR).C-myc and P53 proteins were determined by immunochemistry.The results showed that cadmium chloride increased the hepatocellular telomerase activity in a dose-dependant manner and induced the apoptosis of hepatocytes significantly.The value of relative coefficient between the telomerase activity and the apoptosis rate was 0.9398.RT-PCR revealed that specific bands corresponding to the TERT mRNA,c-myc mRNA,and p53 mRNA were displayed at 185,342 and 538 bp respectively.Cadmium chloride could substantially increase the mRNA expressions of TERT,c-myc and p53 in rat hepatocytes,as compared with control.Moreover,cadmium chloride at the doses of 5,10 and 20 μmol/kg could increase the content of P53 protein in rat hepatocytes obviously,but only that at the doses of 10 and 20 μmol/kg substantially promoted the c-myc protein level in rat hepatocytes.Our study herein suggested that cadmium may contribute to the carcinogenesis by activating telomerase,and overexpressing the mRNAs of TERT,c-myc and p53,and causing apoptosis of normal cells.展开更多
Aim： To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase （hTERT） antisense on tumor necrosis factor-α （TNF-α-induced apoptosis in prostate cancer cells （PC3）. Meth...Aim： To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase （hTERT） antisense on tumor necrosis factor-α （TNF-α-induced apoptosis in prostate cancer cells （PC3）. Methods： Antisense phosphorothioate oligodeoxynucleotide （AS PS-ODN） was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol （TRAP） and polymerase chain reaction enzyme-linked immunoassay （PCR-ELISA）. hTERT mRNA was measured by reverse transcription PCR （RT-PCR） assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-（4, 5-dimethylthiazol-2-yl）-2,5-Diphenyltetrazolium （MTT） assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results： The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide （S PS-ODN） and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion： hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.展开更多
Aim:To evaluate the quantitative detection of human telomerase RNA(hTR)and human telomerase reverse tran-scriptase(hTERT)mRNA as diagnostic parameters in the workup of testicular tissue specimens from patients present...Aim:To evaluate the quantitative detection of human telomerase RNA(hTR)and human telomerase reverse tran-scriptase(hTERT)mRNA as diagnostic parameters in the workup of testicular tissue specimens from patients presentingwith non-obstructive azoospermia.Methods:hTR and hTERT mRNA expression were quantified in 38 cryopre-served testicular tissue specimens by fluorescence real-time reverse transcription-polymerase chain reaction(RT-PCR)in a LightCycler(r).This was paralleled by conventional histological workup in all tissue specimens and additionalsemithin sectioning preparation in cases with maturation arrest(n=12)and Sertoli-cell-only syndrome(n=12).Re-sults;The average normalized hTERT expression(N_(hTERT))was 131.9±48.0 copies(mean±SD)in tissue speci-mens with full spermatogenesis,N_(hTERT)=51.2±17.2 copies in those with maturation arrest and N_(hTERT)=2.7±2.4copies in those with Sertoli-cell-only syndrome(SCOS).The discriminant analysis showed that detection of N_(hTERT)(N_(hTR))had a predictive value of 86.8%(55.3%)for correct classification in one of the three histological subgroups.Conclusion;Our results demonstrate that quantitative detection of hTERT mRNA expression in testicular tissue en-ables a molecular-diagnostic classification of gametogenesis.Quantitative detection of hTERT in testicular biopsies isthus well suited for supplementing the histopathological evaluation.展开更多
Objective To investigate the effects of sodium selenite on telomerase activity, apoptosis and expression of TERT, c-myc and p53 in rat hepatocytes. Methods Selenium at doses of 2.5, 5.0, and 10 μmol/kg was given to S...Objective To investigate the effects of sodium selenite on telomerase activity, apoptosis and expression of TERT, c-myc and p53 in rat hepatocytes. Methods Selenium at doses of 2.5, 5.0, and 10 μmol/kg was given to SD rats by garage. In rat hepatocytes, telomerase activity was measured by the telomeric repeat amplification protocol （TRAP）, apoptosis was detected by flow cytometry, and expressions of telomerase reverse transcriptase （TERT）, c-myc and p53 were analyzed by reverse transcription-polymerase chain reaction （RT-PCR）. c-Myc and P53 proteins were detected by immunochemistry. Results Selenium at doses of 2.5, 5.0, and 10 μmol/kg significantly increased hepatocellular telomerase activity and induced apoptosis in a dose-dependent manner. Although selenium at doses of 2.5, 5.0, and 10 μmol/kg displayed no obvious enhancing effect on the TERT mRNA expression in rat hepatocytes （P〉0.05）, it significantly increased the c-myc mRNA and p53 mRNA expression at the dose of 10 μmol/kg （P〈0.05）. Selenium at doses of 5.0 and 10 μmol/kg obviously increased the content of P53 protein in rat hepatocytes, but only at the dose of 10 μmol/kg, it significantly promoted the value of c-Myc protein in them. Conclusion Selenium can slightly increase telomerase activity and TERT expression, and significantly induce apoptosis and over-expression of c-myc and p53 at relatively high doses. The beneficial effects of selenium on senescence and aging may be mediated by telomerase activation and expression of TERT, c-myc, and p53 in rat hepatocytes.展开更多
AIM： To investigate the effect of telomerase hTERT gene antisense oligonucleotide （hTERT-ASO） on proliferation and telomerase activity of pancreatic cancer cell line Bxpc-3. METHODS： MTT assay was used to detect t...AIM： To investigate the effect of telomerase hTERT gene antisense oligonucleotide （hTERT-ASO） on proliferation and telomerase activity of pancreatic cancer cell line Bxpc-3. METHODS： MTT assay was used to detect the effect of different doses of hTERT-ASO on proliferation of Bxpc-3 cell for different times. To study the anti-tumor activity, the cells were divided into there groups： Control group （pancreatic cancer cell Bxpc-3）; antisense oligonucleotide （hTERT-ASO） group; and nosense oligonucleotide group decorated with phosphorothioate. Telomerase activity was detected using TRAP-PCR-ELISA. Cell DNA distribution was examined using flow cytometry assay. Cell apoptosis was observed by transmission electron microscope in each group. RESULTS： After treatment with 6 mmollL hTERT- ASO, cell proliferation was inhibited in dose- and time- dependent manner. The telomerase activity decreased after treatment with hTERT-ASO for 72 h. Flow cytometry showed the cell number of G0/G1 phase increased from 2.7% to 14.7%, the cell number of S phase decreased from 72.7% to 51.0%, and a sub-G1 stage cell apoptosis peak appeared in front of G1 stage. CONCLUSION： Telomerase antisense oligodeoxy- nucleotide can inhibit the proliferation of pancreatic cancer cell line Bxpc-3 and decrease the telomerase activity and increase cell apoptosis rate in vitro.展开更多
Objective To evaluate the expression of telomerase transcriptional elements-interacting factor （TEIF） in human testis under different status and its relation with human telomerase reverse transcriptase （hTERT） exp...Objective To evaluate the expression of telomerase transcriptional elements-interacting factor （TEIF） in human testis under different status and its relation with human telomerase reverse transcriptase （hTERT） expression. Methods Specific antisera against TEIF were generated by immunization of rabbits with purified recombinated partial TEIF. Samples were assigned to three groups according to their pathological types, including 16 normal testes, 8 atrophic testes, and 6 testicular seminomas. They were subjected to immunohistochemical staining of TEIF and hTERT. Results from both TEIF and hTERT were analyzed semi-quantitatively and compared. The expressions of TEIF and hTERT were detected in all samples of normal, atrophic testes, and seminomas. No differences of TEIF expressions among these three groups were observed （P 〉 0.05）. On the contrary, the expressions of hTERT were significantly lower in atrophic testes compared with those of normal testes and seminomas （both P 〈 0.05）. Nevertheless, co-expressions of TEIF with hTERT were revealed to be in normal and malignant cases （P 〈 0.05） but not in atrophic testes, which generally presented TEIF expression. The cellular distributions of both proteins were similar and mainly in spermatocytes and some Sertoli cells, while were all negative in the interstitial cells and other stromal cells. Conclusion The uniform expressions of TEIF in all these specimens suggest that it may be a marker of testis and its related diseases. The strong expression of hTERT in normal testes and testicular seminomas comparing with the low expression in atrophic testes may suggest a role for telomerase in maintaining proliferation of germ cells.展开更多
Telomeres are non-coding tandem repeats of 1000-2000 TTAGGG nucleotide DNA sequences on the 3’ termini of human chromosomes where they serve as protective “caps” from degradation and loss of genes. The “cap” at t...Telomeres are non-coding tandem repeats of 1000-2000 TTAGGG nucleotide DNA sequences on the 3’ termini of human chromosomes where they serve as protective “caps” from degradation and loss of genes. The “cap” at the end of chromosome required to protect its integ-rity is a 150-200 nucleotide-long single stranded G-rich 3’ overhang that forms two higher order structures, a T-loop with Sheltering complex, or a G-quadruplex com-plex. Telomerase is a human ribonucleoprotein reverse transcriptase that continually added single stranded TTAGGG DNA sequences onto the single strand 3’ of telomere in the 5’ to 3’ direction. Telomerase activity is detected in male germ line cells, proliferative cells of renewal tissues, some adult pluripotent stem cells, embryonic cells, but in most somatic cells is not de-tected. Re-expression or up-regulation of telomerase in tumours cells is considered as a critical step in cell tumorigenesis and telomerase is widely considered as a tumour marker and a target for anticancer drugs. Dif-ferent approaches have been used in anticancer thera-peutics targeting telomerase. Telomerase inhibitors can block directly Human TElomerase Reverse Transcrip-tase （hTERT） or Human TElomerase RNA telomerase subunits activity, or G-quadruplex and Sheltering complex components, shortening telomeres and inhibiting cell proliferation. Telomerase can become an immune target and GV1001, Vx-001, I540 are the most wide-spread vaccines used with encouraging results. Another method is to use hTERT promoter to drive suicide gene expression or to control a lytic virus replication. Recently telomerase activity was used to activate pro-drugs such as Acycloguanosyl 5’-thymidyltriphosphate, a synthetic ACV-derived molecule when it is activated by telomer-ase it does not require any virus or host active immune response to induce suicide gene therapy. Advantage of all these therapies is that target only neoplastic cells without any effects in normal cells, avoiding toxicity and adverse effects of the current chemotherapy. However, as not all the approaches are equally effcient, further studies will be necessary.展开更多
Objective:The aim of the study was to examine the effect of Sp1 on the expression of the human telomerase reverse transcriptase(hTERT) gene in human colorectal carcinoma SW480 cells.Methods:The Sp1 shRNA plasmid was t...Objective:The aim of the study was to examine the effect of Sp1 on the expression of the human telomerase reverse transcriptase(hTERT) gene in human colorectal carcinoma SW480 cells.Methods:The Sp1 shRNA plasmid was transfected into colorectal carcinoma SW480 cells line by liposome mediation for transient expression.After Sp1 shRNA plasmid transfected SW480 cells,the exogenous Sp1 protein expression was determined by the method of Western blot.At same time,hTERT mRNA expression was detected by RT-PCR,telomerase activity was determined by the telomeric repeat amplification protocol(TRAP) assay,and the apoptotic rate of cells was also tested by flow cytometry.Results:The protein expressions of Sp1 gene could be reduce by transfecting of pGenesil-1-Sp1(+) recombinant plasmid into SW480 cells.The apoptotic rate was increased compared with pGenesil-1-Sp1(-)/SW480 and SW480(P < 0.05),which indicated that lowexpression of Sp1 gene could lead to low level of telomerase activity and induce apoptosis.Conclusion:Silencing Sp1 may suppress the activity of telomerase by inhabiting hTERT gene expression.展开更多
Objective: To study the telomerase activity in human renal cell carcinoma and to evaluate the correlation with the clinicobiologic features of the neogrowth.Methods: The telomerase activity was studied by means of a m...Objective: To study the telomerase activity in human renal cell carcinoma and to evaluate the correlation with the clinicobiologic features of the neogrowth.Methods: The telomerase activity was studied by means of a modified telomeric repeat amplification protocol (TRAP) in 32 renal cell carcinoma tissues, 32 normal renal tissues and 32 paracancer tissues and its correlation with the clinicopathologic features of the tumor was evaluated.Results: Telomerase activity was strongly positive in 17, positive in 12 and negative in 3 cases of renal cell carcinoma tissues, the total positive rate being 91%. Telomerase activity was weakly positive (6%) in only 2 out of 32 samples of normal renal cortex tissues and positive in 6 paracancer tissues (19%), the difference was conspicuous (P<0.01).Conclusion: The positive rate of telomerase activity was significantly higher in renal cell carcinoma tissues and might serve as a prognostic marker for estimating the biologic characteristics of renal cell carcinoma.展开更多
基金the Beijing Hope Run Special Fund of Cancer Foundation of China,No.LC2020L05.
文摘BACKGROUND As a critical early event in hepatocellular carcinogenesis,telomerase activation might be a promising and critical biomarker for hepatocellular carcinoma(HCC)patients,and its function in the genesis and treatment of HCC has gained much attention over the past two decades.AIM To perform a bibliometric analysis to systematically assess the current state of research on HCC-related telomerase.METHODS The Web of Science Core Collection and PubMed were systematically searched to retrieve publications pertaining to HCC/telomerase limited to“articles”and“reviews”published in English.A total of 873 relevant publications related to HCC and telomerase were identified.We employed the Bibliometrix package in R to extract and analyze the fundamental information of the publications,such as the trends in the publications,citation counts,most prolific or influential writers,and most popular journals;to screen for keywords occurring at high frequency;and to draw collaboration and cluster analysis charts on the basis of coauthorship and co-occurrences.VOSviewer was utilized to compile and visualize the bibliometric data.RESULTS A surge of 51 publications on HCC/telomerase research occurred in 2016,the most productive year from 1996 to 2023,accompanied by the peak citation count recorded in 2016.Up to December 2023,35226 citations were made to all publications,an average of 46.6 citations to each paper.The United States received the most citations(n=13531),followed by China(n=7427)and Japan(n=5754).In terms of national cooperation,China presented the highest centrality,its strongest bonds being to the United States and Japan.Among the 20 academic institutions with the most publications,ten came from China and the rest of Asia,though the University of Paris Cité,Public Assistance-Hospitals of Paris,and the National Institute of Health and Medical Research(INSERM)were the most prolific.As for individual contributions,Hisatomi H,Kaneko S,and Ide T were the three most prolific authors.Kaneko S ranked first by H-index,G-index,and overall publication count,while Zucman-Rossi J ranked first in citation count.The five most popular journals were the World Journal of Gastroenterology,Hepatology,Journal of Hepatology,Oncotarget,and Oncogene,while Nature Genetics,Hepatology,and Nature Reviews Disease Primers had the most citations.We extracted 2293 keywords from the publications,120 of which appeared more than ten times.The most frequent were HCC,telomerase and human telomerase reverse transcriptase(hTERT).Keywords such as mutational landscape,TERT promoter mutations,landscape,risk,and prognosis were among the most common issues in this field in the last three years and may be topics for research in the coming years.CONCLUSION Our bibliometric analysis provides a comprehensive overview of HCC/telomerase research and insights into promising upcoming research.
基金ThisprojectwassupportedbyagrantfromthefoundationofscientificandtechnologicalkeyprojectofHubeiProvince (No .2 0 0 2AA30 4B10 )
文摘Telomerase activity and the expression of telomerase subunits (for example, telomerase reverse transcriptase and telomerase associated protein 1 and telomerase RNA component) of peripheral white blood cells were detected in the patients with acute myelogenous leukaemia (AML) and the correlation between telomerase activity and the expression of telomerase subunits was observed. In 94 peripheral white blood cells from 18 healthy volunteers and 76 patients with AML, including 31 AML at initial presentation, 24 at relapse and 21 at complete remission, the telomerase activity and telomerase subunits mRNA or RNA were detected by PCR ELISA and RT PCR respectively. The results showed that the positive rate of telomerase from patients with AML at initial presentation, at relapse and at complete remission was 74.1 %, 79.2 % and 4.8 % respectively. The positive rate of telomerase reverse transcriptase mRNA from healthy volunteers, AML at initial presentation, AML at relapse and AML at complete remission was 5.6 %, 80.6 %, 83.3 % and 9.5 % respectively. The positive rate of telomerase associated protein 1 mRNA and telomerase RNA component in all samples were 100 %. It was suggested that the up regulation of telomerase activity and the expression of telomerase reverse transcriptase is correlated closely with the occurrence and relapse of AML, so telomerase activity and the expression of telomerase reverse transcriptase may be used to estimate the curative effect and predict relapse of AML. Moreover, the up regulation of telomerase activity is correlated with the expression of telomerase reverse transcriptase significantly.
基金This project was supported by grants from Foundation of Science and Technology of Guangzhou city (2001-Z-037-01) and Guangdong Province (021195).
文摘Objective: To investigated the e?ect of inhibition of telomerase with hTERT antisense on leukemic cells (HL-60 and K562) to CDDP-induced apoptosis. Methods: Antisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and puri?ed. Telomerase activity was detected by Telomerase PCR ELASA kit and cell apoptosis was observed by morphological method and determined by ?owcytometry. Results: AS PS-ODN could signi?cantly inhibit telomerase activity by down regulat- ing the hTERT expression, and increase the susceptibility of leukemic cells to CDDP-induced apoptosis. Conclusion: Inhibition of telomerase with hTERT antisense can increases the susceptibility of leukemic cells to CDDP-induced apoptosis.
基金National Science Foundation for Distinguished YouthScholar ( 30225038) the Major State Basic Re-search Development Programof China (00CB510103).
文摘Aim To investigate the effects of trichostatin A （TSA） on telomerase activity and the expression of human telomerase reverse transcriptase （hTERT） during apoptosis in vitro and the mechanisms in HL-60 cells. Methods The proliferative activity of HL-60 cells was assessed by MTT assay. Cell apoptosis was analyzed by flow cytometry. Telomerase activity was examined by TRAP-ELISA. The expression of telomerase subunits was analyzed by RT-PCR. Results A time- and dose-dependent inhibition was detected in HL-60 cells treated with TSA. After treatment with 600 nmol· L^-1 TSA for 48 h, the apoptosis rate in HL-60 cells was 42. 6% and telomerase activity decreased 1.95 ± 0.25, 1.73 ± 0. 12, and 1.52 ± 0. 09 for 12, 24, and 48 h, respectively. The expression of hTERTmRNA decreased. No significant changes were observed in the expression of hTRmRNA and hTPI mRNA. Condusion TSA inhibits telomerase activity and induces apoptosis in HL-60 cells. The underlying mechanism may be related to the down-regulation of hTERT transcription.
文摘To detect the expression of telomerase subunits （human telomerase reverse transcriptase, human telomerase associated protein 1 and human telomerase RNA） in gastric cancer and to examine the role that different telomerase subunits play in the gastric carcinogenesis, reverse transcription-polymerase chain reaction （RT-PCR） was used to detect telomerase suhunits messenger RNA in 24 samples of gastric cancer and corresponding non-cancerous tissue. The results showed that the positive rate of hTERT mRNA from gastric cancer and corresponding non-cancerous tissues was 100% and 25 %, respectively. The former was significantly higher than the latter （X^2 = 26.4, P〈0.01）. The positive rate of hTEP1 mRNA from gastric cancer and corresponding non-cancerous tissues was 100 % and 91.7%, respectively and no significant difference was found between them （X^2 =2.1, P〉0.05）. The positive rates of hTR for gastric cancer and corresponding non-cancerous tissues were both 100 % and no significant difference existed between them. It is concluded that in contrast to hTEP1 and hTR, the up-regulation of hTERT mRNA expression may play a more important role in the development of gastric cancer.
基金Supported by the Science and Research Foundation of Bureau of Health, Hunan Province, China, No. Y02-083
文摘AIM: To investigate synergism of inhibition of telomerase activity and proliferation of human colon cancer cells by combination of telomerase antisense oligonucleotides (ASODNs) simultaneously targeting human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) in vitro. METHODS: ASODN of hTR and ASODN of hTERT were transfected into human colon cancer SW480 cells by liposomal transfection reagents. Telomerase activity of SW480 cells was examined using telomeric repeat amplification protocol (TRAP)-enzyme-linked immunosorbent assay (PCR-ELISA). Proliferation activity of SW480 cells was tested by methyl thiazolyl tetrazolium assay. Apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: The telomerase activity and cell survival rate in SW480 cells transfected with 0.2 μmol/L of ASODN of hTR or ASODN of hTERT for 24-72 h were significantly decreased in a time-dependent manner compared with those after treatment with sense oligonucleotides and untreated (telomerase activity: 24 h, 73%, 74% vs99%, 98%; 48 h, 61%, 55% vs98%, 99%; 72 h, 41%, 37% vs 99%, 97%; P<0.01; cell survival rate: 24 h, 88%, 86% vs594%, 98%; 48 h, 49%, 47% vs94%, 97%; 72 h, 44%, 42% vs92%, 96%; P<0.01). Moreover, the telomerase activity and the cell survival rate in SW480 cells treated by the combination of telomerase anti-hTR and anti-hTERT were more significantly suppressed than single anti-hTR or anti-hTERT (telomerase activity: 24 h, 59% vs 73%, 74%; 48 h, 43% vs61%, 55%; 72 h, 18% vs41%, 37%; P<0.01; cell survival rate: 24 h, 64% vs88%, 86%; 48 h, 37% vs49%, 47%; 72 h, 25% vs44%, 42%; P<0.01). Meanwhile, the apoptosis rates in the combination group were markedly increased compared with those in the single group (24 h, 18.0% vs7.2%, 7.4%; 48 h, 23.0% vs13.0%, 14.0%; 72 h, 28.6% vs 13.2%, 13.75; P<0.01). Cells in combination group were arrested at G0/G1 phase. CONCLUSION: Telomerase anti-hRT and anti-hTERT suppress telomerase activity, and inhibit growth of human colon cancer cells probably via induction of apoptosis and retardation of cell cycle. Additionally, combined use of telomerase ASODNs targeting both hTR and hTERT yields synergistic action selective for human colon cancer.
文摘A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was better in reproducibility and accuracy. Using this method, we found telomerase activities were absent in normal human liver cells, while detected in ail of four human hepatoma cell lines (BEL-7404, SMMC-7721, QGY-7903 and HCCM) without significant differences.
基金Supported by Scientific Foundation of Guangdong Pharmaceutical University, No. 2006GGW01National Natural ScienceFoundation of China,No. 30271110.
文摘To investigate the effects of sodium selenite on telomerase activity and expression of hTERT mRNA in cadmium-transformed 16HBE cells. Methods Telomerase activity and expression of genes were measured after cultured cadmium-transformed 16HBE cells were exposed to sodium selenite at different doses （0.625, 1.25, 2.50, 5.00 pmol/L） for 24 hours. Results Selenium decreased telomerase activity in cadmium-transformed 16HBE cells. There existed an obvious dose-effect relationship between the selenium concentration and these changes. The expression of hTERT and c-myc mRNA also decreased but the expression of madl mRNA increased after exposure to selenium for 24 hours. No difference was found in expression of hTRF1 and hTRF2 mRNA after incubated with sodium selenite for 24 hours, compared with control group. Conclusion Selenium inhibits telomerase activity by decreasing hTERT and c-myc mRNA expression and increasing madl mRNA expression in cadmium-transformed 16HBE cells and selenium concentration is significantly correlated with these changes.
基金Supported by National Natural Science Foundation of China,No.30270609
文摘AIM: To investigate telomerase activity and human telomerase reverse transcriptase (hTERT) expression in normal human gastric mucosal epithelial cells (nhGMECs) and fibroblasts (nhGMFs).
基金Supported by A grant from Cariparo,Project"Tumour mi-croenvironment and tumour spread in gastrointestinal cancers",2013/2014,No.6421 to Rampazzo E
文摘Colorectal cancer(CRC)is the third most common cancer worldwide and,despite improved treatments,is still an important cause of cancer-related deaths.CRC encompasses a complex of diseases arising from a multistep process of genetic and epigenetic events.Besides heterogeneity in the molecular and biological features of CRC,chromosomal instability is a hallmark of cancer and cancer cells may also circumvent replicative senescence and acquire the ability to sustain unlimited proliferation.Telomere/telomerase interplay is an important mechanism involved in both genomic stability and cellular replicative potential,and its dysfunction plays a key role in the oncogenetic process.The erosion of telomeres,mainly because of cell proliferation,may be accelerated by specific alterations in the genes involved in CRC,such as APC and MSH2.Although there is general agreement that the shortening of telomeres plays a role in the early steps of CRC carcinogenesis by promoting chromosomal instability,the prognostic role of telomere length in CRC is still under debate.The activation of telomerase reverse transcriptase(TERT),the catalytic component of the telomerase complex,allows cancer cells to grow indefinitely by maintaining the length of the telomeres,thus favouring tumour formation/progression.Several studies indicate that TERT increases with disease progression,and most studies suggest that telomerase is a useful prognostic factor.Plasma TERT mRNA may also be a promising marker for the minimally invasive monitoring of disease progression and response to therapy.
基金supported by the National Natural Sciences Foundation of China(No.30271110)Scientific Foundation(No.2006GGW01)Teacher's Foundation of Guangdong Pharmaceutical University,China
文摘This study investigated the effect of cadmium on the telomerase activity,the expression of TERT,c-myc and p53 and the apoptosis of rat hepatocytes.The rats were administrated 5,10 and 20 μmol/kg cadmium chloride intraperitoneally and sacrificed 48 h after the initial treatment.The telomerase activity of the rat hepatocytes was measured by the telomeric repeat amplification protocol (TRAP),and apoptosis was detected by flow cytometry.The mRNA expressions of TERT,c-myc and p53 were measured by reverse transcription-polymerase chain reaction (RT-PCR).C-myc and P53 proteins were determined by immunochemistry.The results showed that cadmium chloride increased the hepatocellular telomerase activity in a dose-dependant manner and induced the apoptosis of hepatocytes significantly.The value of relative coefficient between the telomerase activity and the apoptosis rate was 0.9398.RT-PCR revealed that specific bands corresponding to the TERT mRNA,c-myc mRNA,and p53 mRNA were displayed at 185,342 and 538 bp respectively.Cadmium chloride could substantially increase the mRNA expressions of TERT,c-myc and p53 in rat hepatocytes,as compared with control.Moreover,cadmium chloride at the doses of 5,10 and 20 μmol/kg could increase the content of P53 protein in rat hepatocytes obviously,but only that at the doses of 10 and 20 μmol/kg substantially promoted the c-myc protein level in rat hepatocytes.Our study herein suggested that cadmium may contribute to the carcinogenesis by activating telomerase,and overexpressing the mRNAs of TERT,c-myc and p53,and causing apoptosis of normal cells.
文摘Aim： To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase （hTERT） antisense on tumor necrosis factor-α （TNF-α-induced apoptosis in prostate cancer cells （PC3）. Methods： Antisense phosphorothioate oligodeoxynucleotide （AS PS-ODN） was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol （TRAP） and polymerase chain reaction enzyme-linked immunoassay （PCR-ELISA）. hTERT mRNA was measured by reverse transcription PCR （RT-PCR） assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-（4, 5-dimethylthiazol-2-yl）-2,5-Diphenyltetrazolium （MTT） assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results： The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide （S PS-ODN） and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion： hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.
文摘Aim:To evaluate the quantitative detection of human telomerase RNA(hTR)and human telomerase reverse tran-scriptase(hTERT)mRNA as diagnostic parameters in the workup of testicular tissue specimens from patients presentingwith non-obstructive azoospermia.Methods:hTR and hTERT mRNA expression were quantified in 38 cryopre-served testicular tissue specimens by fluorescence real-time reverse transcription-polymerase chain reaction(RT-PCR)in a LightCycler(r).This was paralleled by conventional histological workup in all tissue specimens and additionalsemithin sectioning preparation in cases with maturation arrest(n=12)and Sertoli-cell-only syndrome(n=12).Re-sults;The average normalized hTERT expression(N_(hTERT))was 131.9±48.0 copies(mean±SD)in tissue speci-mens with full spermatogenesis,N_(hTERT)=51.2±17.2 copies in those with maturation arrest and N_(hTERT)=2.7±2.4copies in those with Sertoli-cell-only syndrome(SCOS).The discriminant analysis showed that detection of N_(hTERT)(N_(hTR))had a predictive value of 86.8%(55.3%)for correct classification in one of the three histological subgroups.Conclusion;Our results demonstrate that quantitative detection of hTERT mRNA expression in testicular tissue en-ables a molecular-diagnostic classification of gametogenesis.Quantitative detection of hTERT in testicular biopsies isthus well suited for supplementing the histopathological evaluation.
基金supported by the Scientific Foundation and Teacher’s Foundation of Guangdong Pharmaceutical University (No.2006GGW01)the National Natural Science Foundation of China (No.30271110)
文摘Objective To investigate the effects of sodium selenite on telomerase activity, apoptosis and expression of TERT, c-myc and p53 in rat hepatocytes. Methods Selenium at doses of 2.5, 5.0, and 10 μmol/kg was given to SD rats by garage. In rat hepatocytes, telomerase activity was measured by the telomeric repeat amplification protocol （TRAP）, apoptosis was detected by flow cytometry, and expressions of telomerase reverse transcriptase （TERT）, c-myc and p53 were analyzed by reverse transcription-polymerase chain reaction （RT-PCR）. c-Myc and P53 proteins were detected by immunochemistry. Results Selenium at doses of 2.5, 5.0, and 10 μmol/kg significantly increased hepatocellular telomerase activity and induced apoptosis in a dose-dependent manner. Although selenium at doses of 2.5, 5.0, and 10 μmol/kg displayed no obvious enhancing effect on the TERT mRNA expression in rat hepatocytes （P〉0.05）, it significantly increased the c-myc mRNA and p53 mRNA expression at the dose of 10 μmol/kg （P〈0.05）. Selenium at doses of 5.0 and 10 μmol/kg obviously increased the content of P53 protein in rat hepatocytes, but only at the dose of 10 μmol/kg, it significantly promoted the value of c-Myc protein in them. Conclusion Selenium can slightly increase telomerase activity and TERT expression, and significantly induce apoptosis and over-expression of c-myc and p53 at relatively high doses. The beneficial effects of selenium on senescence and aging may be mediated by telomerase activation and expression of TERT, c-myc, and p53 in rat hepatocytes.
文摘AIM： To investigate the effect of telomerase hTERT gene antisense oligonucleotide （hTERT-ASO） on proliferation and telomerase activity of pancreatic cancer cell line Bxpc-3. METHODS： MTT assay was used to detect the effect of different doses of hTERT-ASO on proliferation of Bxpc-3 cell for different times. To study the anti-tumor activity, the cells were divided into there groups： Control group （pancreatic cancer cell Bxpc-3）; antisense oligonucleotide （hTERT-ASO） group; and nosense oligonucleotide group decorated with phosphorothioate. Telomerase activity was detected using TRAP-PCR-ELISA. Cell DNA distribution was examined using flow cytometry assay. Cell apoptosis was observed by transmission electron microscope in each group. RESULTS： After treatment with 6 mmollL hTERT- ASO, cell proliferation was inhibited in dose- and time- dependent manner. The telomerase activity decreased after treatment with hTERT-ASO for 72 h. Flow cytometry showed the cell number of G0/G1 phase increased from 2.7% to 14.7%, the cell number of S phase decreased from 72.7% to 51.0%, and a sub-G1 stage cell apoptosis peak appeared in front of G1 stage. CONCLUSION： Telomerase antisense oligodeoxy- nucleotide can inhibit the proliferation of pancreatic cancer cell line Bxpc-3 and decrease the telomerase activity and increase cell apoptosis rate in vitro.
基金Supported by N ationalN aturalScienceFoundation ofC hina (30170364 )and a grantfrom the CenterofH um an G enetic D isease,Peking Univ-ersit.y
文摘Objective To evaluate the expression of telomerase transcriptional elements-interacting factor （TEIF） in human testis under different status and its relation with human telomerase reverse transcriptase （hTERT） expression. Methods Specific antisera against TEIF were generated by immunization of rabbits with purified recombinated partial TEIF. Samples were assigned to three groups according to their pathological types, including 16 normal testes, 8 atrophic testes, and 6 testicular seminomas. They were subjected to immunohistochemical staining of TEIF and hTERT. Results from both TEIF and hTERT were analyzed semi-quantitatively and compared. The expressions of TEIF and hTERT were detected in all samples of normal, atrophic testes, and seminomas. No differences of TEIF expressions among these three groups were observed （P 〉 0.05）. On the contrary, the expressions of hTERT were significantly lower in atrophic testes compared with those of normal testes and seminomas （both P 〈 0.05）. Nevertheless, co-expressions of TEIF with hTERT were revealed to be in normal and malignant cases （P 〈 0.05） but not in atrophic testes, which generally presented TEIF expression. The cellular distributions of both proteins were similar and mainly in spermatocytes and some Sertoli cells, while were all negative in the interstitial cells and other stromal cells. Conclusion The uniform expressions of TEIF in all these specimens suggest that it may be a marker of testis and its related diseases. The strong expression of hTERT in normal testes and testicular seminomas comparing with the low expression in atrophic testes may suggest a role for telomerase in maintaining proliferation of germ cells.
文摘Telomeres are non-coding tandem repeats of 1000-2000 TTAGGG nucleotide DNA sequences on the 3’ termini of human chromosomes where they serve as protective “caps” from degradation and loss of genes. The “cap” at the end of chromosome required to protect its integ-rity is a 150-200 nucleotide-long single stranded G-rich 3’ overhang that forms two higher order structures, a T-loop with Sheltering complex, or a G-quadruplex com-plex. Telomerase is a human ribonucleoprotein reverse transcriptase that continually added single stranded TTAGGG DNA sequences onto the single strand 3’ of telomere in the 5’ to 3’ direction. Telomerase activity is detected in male germ line cells, proliferative cells of renewal tissues, some adult pluripotent stem cells, embryonic cells, but in most somatic cells is not de-tected. Re-expression or up-regulation of telomerase in tumours cells is considered as a critical step in cell tumorigenesis and telomerase is widely considered as a tumour marker and a target for anticancer drugs. Dif-ferent approaches have been used in anticancer thera-peutics targeting telomerase. Telomerase inhibitors can block directly Human TElomerase Reverse Transcrip-tase （hTERT） or Human TElomerase RNA telomerase subunits activity, or G-quadruplex and Sheltering complex components, shortening telomeres and inhibiting cell proliferation. Telomerase can become an immune target and GV1001, Vx-001, I540 are the most wide-spread vaccines used with encouraging results. Another method is to use hTERT promoter to drive suicide gene expression or to control a lytic virus replication. Recently telomerase activity was used to activate pro-drugs such as Acycloguanosyl 5’-thymidyltriphosphate, a synthetic ACV-derived molecule when it is activated by telomer-ase it does not require any virus or host active immune response to induce suicide gene therapy. Advantage of all these therapies is that target only neoplastic cells without any effects in normal cells, avoiding toxicity and adverse effects of the current chemotherapy. However, as not all the approaches are equally effcient, further studies will be necessary.
基金Supported by grants from the Natural Science Foundation of Shanxi Province, National Natural Science Foundation,and University Technology Development Project of Shanxi Province, China
文摘Objective:The aim of the study was to examine the effect of Sp1 on the expression of the human telomerase reverse transcriptase(hTERT) gene in human colorectal carcinoma SW480 cells.Methods:The Sp1 shRNA plasmid was transfected into colorectal carcinoma SW480 cells line by liposome mediation for transient expression.After Sp1 shRNA plasmid transfected SW480 cells,the exogenous Sp1 protein expression was determined by the method of Western blot.At same time,hTERT mRNA expression was detected by RT-PCR,telomerase activity was determined by the telomeric repeat amplification protocol(TRAP) assay,and the apoptotic rate of cells was also tested by flow cytometry.Results:The protein expressions of Sp1 gene could be reduce by transfecting of pGenesil-1-Sp1(+) recombinant plasmid into SW480 cells.The apoptotic rate was increased compared with pGenesil-1-Sp1(-)/SW480 and SW480(P < 0.05),which indicated that lowexpression of Sp1 gene could lead to low level of telomerase activity and induce apoptosis.Conclusion:Silencing Sp1 may suppress the activity of telomerase by inhabiting hTERT gene expression.
文摘Objective: To study the telomerase activity in human renal cell carcinoma and to evaluate the correlation with the clinicobiologic features of the neogrowth.Methods: The telomerase activity was studied by means of a modified telomeric repeat amplification protocol (TRAP) in 32 renal cell carcinoma tissues, 32 normal renal tissues and 32 paracancer tissues and its correlation with the clinicopathologic features of the tumor was evaluated.Results: Telomerase activity was strongly positive in 17, positive in 12 and negative in 3 cases of renal cell carcinoma tissues, the total positive rate being 91%. Telomerase activity was weakly positive (6%) in only 2 out of 32 samples of normal renal cortex tissues and positive in 6 paracancer tissues (19%), the difference was conspicuous (P<0.01).Conclusion: The positive rate of telomerase activity was significantly higher in renal cell carcinoma tissues and might serve as a prognostic marker for estimating the biologic characteristics of renal cell carcinoma.
